Broadcast Signal Sending Method, Broadcast Signal Receiving Method, Network Device, and Terminal Device

ABSTRACT

A broadcast signalling method performed by a network device having a protocol stack of with first and second protocol layers where the second protocol layer is below the first protocol layer, the method including generating, by the network device, first information at the first protocol layer, generating, by the network device, second information at the second protocol layer, where the second information is used to determine a time-frequency resource corresponding to one or more synchronization signal blocks (SSBs), processing, by the network device, the first information and the second information at the second protocol layer, and sending, by the network device to a terminal device by using a physical broadcast channel (PBCH) in the one or more SSBs, data obtained after second protocol layer processing.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of International Application No.PCT/CN2018/085186, filed on Apr. 28, 2018, which claims priority toChinese Patent Application No. 201710313613.4, filed on May 5, 2017. Thedisclosures of the aforementioned applications are hereby incorporatedby reference in their entireties.

TECHNICAL FIELD

This application relates to the field of communications technologies,and in particular, to a broadcast signal sending method, a broadcastsignal receiving method, a network device, and a terminal device.

BACKGROUND

In a long term evolution (LTE) network, to support cell search, twodownlink synchronization signals are defined: a primary synchronizationsignal (PSS) and a secondary synchronization signal (SSS). After userequipment (UE) completes a cell search process, the UE has achieveddownlink synchronization with a cell. In this case, the UE needs toobtain system information of the cell to know how the cell isconfigured, to access the cell and correctly work in the cell. Thesystem information includes a master information block (MIB) and asystem information block (SIB). The MIB is sent by a base station to UEby using a physical broadcast channel (PBCH). The synchronization signaland the PBCH separately occupy different time-frequency resources.

In research of a new radio access technology (NR), a concept of asynchronization signal (SS) block (SS block, SSB) is introduced inconsideration of a plurality of beams. There is a configurable mappingrelationship between a beam and an SSB. For example, each of a pluralityof beams is used to send a different SSB, or two beams may be used tosend a same SSB. Each SSB includes an orthogonal frequency divisionmultiplexing (OFDM) symbol used to transmit a PSS, an OFDM symbol usedto transmit an SSS, and an OFDM symbol used to transmit a PBCH. A basestation sends a synchronization signal and a PBCH in an SSB by usingdifferent time-frequency resources.

One or more SSBs form one SS burst, and one or more SS bursts form oneSS burst set. Therefore, one SS burst set includes one or more SSBs. OneSS burst set is mapped to a predetermined quantity of radio frames forsending. For example, one SS burst set is mapped to two radio frames forsending. In this way, the base station sends the SS burst setperiodically, and a period for sending the SS burst set is thepredetermined quantity of radio frames.

In consideration of the foregoing sending manner of the SSB, someadditional information needs to be carried in the SSB, to implementdetection on the SSB by the UE or implement more functions. For example,because one SS burst set may include a plurality of SSBs, an SSB needsto include information used to indicate a ranking of the SSB in asending period of an SS burst set to which the SSB belongs, todistinguish the SSB from another SSB that belongs to a same SS burstset.

How to carry the additional information in the SSB is a problem that isstill under discussion.

SUMMARY

Embodiments of this application provide a broadcast signal sendingmethod and a broadcast signal receiving method, to carry additionalinformation in an SSB.

According to a first aspect, a broadcast signal sending method isprovided. The method is performed by a network device, a protocol stackof the network device includes a first protocol layer and a secondprotocol layer, the second protocol layer is a protocol layer below thefirst protocol layer, and the method includes generating, by the networkdevice, first information at the first protocol layer, generating, bythe network device, second information at the second protocol layer,where the second information is used to determine a time-frequencyresource corresponding to one or more synchronization signal blocksSSBs, processing, by the network device, the first information and thesecond information at the second protocol layer, and sending, by thenetwork device to a terminal device by using a physical broadcastchannel PBCH in the SSB, data obtained after second protocol layerprocessing.

In this embodiment of this application, the network device can send thesecond information to the terminal device on the PBCH only by processingat a protocol layer below the first protocol layer. Compared with asolution in which all information transmitted on the PBCH is processedin an entire protocol stack below the first protocol layer, thissolution shortens a time consumed to process, in the protocol stack, theinformation transmitted on the PBCH, and helps shorten a service delay.

In a possible implementation, the second protocol layer is a mediaaccess control (MAC) layer or a physical layer.

In a possible implementation, the second protocol layer is the physicallayer, and the sending, by the network device to a terminal device byusing a PBCH in the SSB, data obtained after second protocol layerprocessing includes sending, by the network device to the terminaldevice by using the PBCH in the SSB, data obtained after physical layerprocessing.

In a possible implementation, the second protocol layer is the MAClayer, and the sending, by the network device to a terminal device byusing a PBCH in the SSB, data obtained after second protocol layerprocessing includes performing, by the network device, physical layerprocessing on the data obtained by second protocol layer processing, andsending, by the network device to the terminal device by using the PBCHin the SSB, data obtained after physical layer processing.

In a possible implementation, the physical layer processing includes oneor more of the following manners: channel coding, rate matching,scrambling, modulation, time-frequency resource mapping, and inversefast Fourier transform (IFFT) processing.

In a possible implementation, the second information is a sequencenumber of the synchronization signal block SSB.

In a possible implementation, the physical layer processing includeschannel coding, rate matching, scrambling, modulation, resource mapping,and inverse fast Fourier transform, and the performing, by the networkdevice, physical layer processing on the first information and thesecond information includes performing, by the network device, channelcoding and/or rate matching by using the first information and thesecond information as a whole, performing, by the network device,scrambling processing on a result of the channel coding and/or the ratematching by separately using one of J different scrambling codes, toobtain a corresponding scrambling result, where each of N differentscrambling codes of the J scrambling codes corresponds to one type ofvalues of the last M bits of a system frame number, J, N, and M are allnatural numbers, 1≤N≤J, and N=M², performing, by the network device,modulation processing on the scrambling result, to obtain modulateddata, and mapping, by the network device, the modulated data to a PBCHin the SSB corresponding to the sequence number of the SSB, andperforming IFFT processing on data mapped to each PBCH symbol, to obtainthe data obtained after physical layer processing.

In a possible implementation, the physical layer processing includeschannel coding, rate matching, scrambling, modulation, resource mapping,and inverse fast Fourier transform, and the performing, by the networkdevice, physical layer processing on the first information and thesecond information includes performing, by the network device, channelcoding and/or rate matching on the first information by using a firstcoding rate, to obtain a first coding result, and performing, by thenetwork device, channel coding and/or rate matching on the secondinformation by using a second coding rate, to obtain a second codingresult, performing, by the network device, scrambling processing on acombination of the first coding result and the second coding result byseparately using one of J different scrambling codes, to obtain acorresponding scrambling result, where each of N different scramblingcodes of the J scrambling codes corresponds to one type of values of thelast M bits of a system frame number, J, N, and M are all naturalnumbers, 1≤N≤J, and N=M², performing, by the network device, modulationprocessing on the scrambling result, to obtain modulated data, andmapping, by the network device, the modulated data to a PBCH in the SSBcorresponding to the sequence number of the SSB, and performing IFFTprocessing on data mapped to each PBCH symbol, to obtain the dataobtained after physical layer processing.

In a possible implementation, the physical layer processing includeschannel coding, rate matching, scrambling, modulation, resource mapping,and inverse fast Fourier transform, and the performing, by the networkdevice, physical layer processing on the first information and thesecond information includes performing, by the network device, channelcoding and/or rate matching on the first information by using a firstcoding rate, to obtain a first coding result, and performing, by thenetwork device, channel coding and/or rate matching on the secondinformation by using a second coding rate, to obtain a second codingresult, separately performing, by the network device, scramblingprocessing on the first coding result and the second coding result byseparately using one of J different scrambling codes, to obtain acorresponding first scrambling result and a corresponding secondscrambling result, where each of N different scrambling codes of the Jscrambling codes corresponds to one type of values of the last M bits ofa system frame number, J, N, and M are all natural numbers, 1≤N≤J, andN=M², performing, by the network device, modulation processing on acombination of the first scrambling result and the second scramblingresult, to obtain modulated data, and mapping, by the network device,the modulated data to a PBCH in the SSB corresponding to the sequencenumber of the SSB, and performing IFFT processing on data mapped to eachPBCH symbol, to obtain the data obtained after physical layerprocessing.

In a possible implementation, the physical layer processing includeschannel coding, rate matching, scrambling, modulation, resource mapping,and inverse fast Fourier transform, and the performing, by the networkdevice, physical layer processing on the first information and thesecond information includes performing, by the network device, channelcoding and/or rate matching on the first information by using a firstcoding rate, to obtain a first coding result, and performing, by thenetwork device, channel coding and/or rate matching on the secondinformation by using a second coding rate, to obtain a second codingresult, separately performing, by the network device, scramblingprocessing on the first coding result and the second coding result byseparately using one of J different scrambling codes, to obtain acorresponding first scrambling result and a corresponding secondscrambling result, where each of N different scrambling codes of the Jscrambling codes corresponds to one type of values of the last M bits ofa system frame number, J, N, and M are all natural numbers, 1≤N≤J, andN=M², separately performing, by the network device, modulationprocessing on the first scrambling result and the second scramblingresult, to obtain corresponding first modulated data and correspondingsecond modulated data, and mapping, by the network device, a combinationof the first modulated data and the second modulated data to a PBCH inthe SSB corresponding to the sequence number of the SSB, and performingIFFT processing on data mapped to each PBCH symbol, to obtain the dataobtained after physical layer processing.

In a possible implementation, the physical layer processing includeschannel coding, rate matching, scrambling, modulation, resource mapping,and inverse fast Fourier transform, and the performing, by the networkdevice, physical layer processing on the first information and thesecond information includes performing, by the network device, channelcoding and/or rate matching on the first information by using a firstcoding rate, to obtain a first coding result, and performing, by thenetwork device, channel coding and/or rate matching on the secondinformation by using a second coding rate, to obtain a second codingresult, separately performing, by the network device, scramblingprocessing on the first coding result and the second coding result byseparately using one of J different scrambling codes, to obtain acorresponding first scrambling result and a corresponding secondscrambling result, where each of N different scrambling codes of the Jscrambling codes corresponds to one type of values of the last M bits ofa system frame number, J, N, and M are all natural numbers, 1≤N≤J, andN=M², separately performing, by the network device, modulationprocessing on the first scrambling result and the second scramblingresult, to obtain corresponding first modulated data and correspondingsecond modulated data, mapping, by the network device, the firstmodulated data to a first resource of a PBCH in the SSB corresponding tothe sequence number of the SSB, to obtain a first mapped result, andmapping the second modulated data to a second resource of the PBCH inthe SSB corresponding to the sequence number of the SSB, to obtain asecond mapped result, and separately performing, by the network device,inverse Fast Fourier transform IFFT processing on the first mappedresult and the second mapped result, to obtain a first IFFT result and asecond IFFT result, where the first IFFT result and the second IFFTresult are the data obtained after physical layer processing.

After encoding is performed at a relatively low coding rate, a decodingresult obtained when the terminal device performs corresponding decodinghas relatively high reliability. The second information has a relativelyhigh timeliness requirement on control over the behavior of the terminaldevice, and therefore, the second information may be encoded at arelatively low coding rate. In this way, the terminal device may notneed to combine the second information detected in a plurality offrames, and may perform time sequence alignment based only on the secondinformation detected in one frame, thereby greatly accelerating timesequence alignment. Optionally, in the foregoing several possibleimplementations, the first coding rate is greater than the second codingrate.

In a possible implementation, the first information includes systeminformation. The system information includes one or more of thefollowing: a system bandwidth parameter value, first L-M bits of asystem frame number, or configuration information of remaining minimumsystem information, where the system frame number includes a total of Lbits, L and M are both natural numbers, and 1≤M≤L.

In a possible implementation, the first protocol layer is an RRC layer.

According to a second aspect, a broadcast signal receiving method isprovided. The method is performed by a terminal device, a protocol stackof the terminal device includes a first protocol layer and a secondprotocol layer, the first protocol layer is a protocol layer above thefirst protocol layer, and the method includes receiving, by the terminaldevice, data sent by a network device by using a physical broadcastchannel PBCH, performing, by the terminal device, physical layerprocessing on the received data, obtaining, by the terminal device atthe second protocol layer, first information and second information froma physical layer processing result, where the second information is usedto determine a time-frequency resource corresponding to one or moresynchronization signal blocks SSBs carrying the first information,controlling, by the terminal device at the second protocol layer, abehavior of the terminal device based on the second information, andcontrolling, by the terminal device at the first protocol layer, abehavior of the terminal device based on the first information.

In the broadcast signal receiving method provided in this embodiment ofthis application, after processing, at the physical layer, the data senton the PBCH, the terminal device does not need to report, to the firstprotocol layer for processing, all data obtained after physical layerprocessing, and instead may directly read the second information thereofat the second protocol layer, and control the behavior of the terminaldevice based on the second information. Because a time taken by theterminal device to process the second information in a protocol stack isshortened, a service delay can be shortened, and timeliness of a servicecan be improved.

In a possible implementation, the second protocol layer is a physicallayer or a MAC layer.

In a possible implementation, the second protocol layer is the MAClayer, and the obtaining, by the terminal device at the second protocollayer, first information and second information from a physical layerprocessing result includes processing, by the terminal device at thesecond protocol layer, the physical layer processing result, andobtaining, by the terminal device, the first information and the secondinformation from data obtained after second protocol layer processing.

In a possible implementation, the receiving, by the terminal device,data sent by a network device by using a PBCH includes detecting, by theterminal device, a synchronization signal, and determining, by using thesynchronization signal, a cell identifier and a time-frequency resourcethat corresponds to the PBCH, and receiving, on the time-frequencyresource that corresponds to the PBCH, the data sent by the networkdevice by using the PBCH.

In a possible implementation, the performing, by the terminal device,physical layer processing on the received data includes performing fastFourier transform FFT processing on received data that is sent by a basestation by using a PBCH, demodulating data obtained by the FFTprocessing, to obtain demodulated data, obtaining J descramblingsequences according to the cell identifier, selecting, by the terminaldevice, a descrambling sequence from the J descrambling sequences todescramble the demodulated data, and performing, by the terminal device,channel decoding on data obtained by descrambling, and performing CRCcheck on data obtained by channel decoding, to determine a descramblingsequence that can be used to correctly descramble the demodulated data.A channel decoding result obtained by correct descrambling is used as aphysical layer processing result, so that UE obtains the firstinformation and the second information from the physical layerprocessing result, where the physical layer processing result includesthe first information and the second information.

In a possible implementation, the performing, by the terminal device,physical layer processing on the received data includes performing FFTprocessing on received data that is sent by a base station by using aPBCH, demodulating data obtained by FFT processing, to obtaindemodulated data, obtaining J descrambling sequences according to thecell identifier, selecting, by the terminal device, a descramblingsequence from the J descrambling sequences to descramble the demodulateddata, obtaining, by the terminal device, included first data and seconddata from the descrambled data, and performing, by the terminal device,channel decoding on the first data by using a first decoding rate, andperforming CRC check on data obtained by channel decoding, to determinea descrambling sequence that can be used to correctly descramble thedemodulated data. A channel decoding result obtained by correctdescrambling is used as the first information. Channel decoding isperformed on the second data by using a second decoding rate, and CRCcheck is performed on the data obtained by channel decoding, todetermine a descrambling sequence that can be used to correctlydescramble the demodulated data. A channel decoding result obtained bycorrect descrambling is used as the second information.

Corresponding to the coding rates, the first decoding rate is greaterthan the second decoding rate. Because a coding rate used when the basestation encodes the second information is relatively low, decodingaccuracy of corresponding decoding performed by the terminal device isrelatively high. Optionally, in the foregoing possible implementations,the first decoding rate is greater than the second decoding rate.

In a possible implementation, the first information includes systeminformation. The system information includes a system bandwidth, firstL-M bits of a system frame number, or configuration information ofremaining minimum system information, where the system frame numberincludes a total of L bits, L and M are both natural numbers, and 1≤M≤L.

In a possible implementation, the second information is a sequencenumber of the synchronization signal block SSB.

In a possible implementation, the first protocol layer is an RRC layer.

According to a third aspect, a network device is provided. The networkdevice has a function of implementing the method in the first aspect orany possible implementation of the first aspect. The function may beimplemented by using hardware, or implemented by hardware executingcorresponding software. The hardware or the software includes one ormore modules corresponding to the foregoing function.

According to a fourth aspect, a terminal device is provided. Theterminal device has a function of implementing the method in the secondaspect or any possible implementation of the second aspect. The functionmay be implemented by using hardware, or implemented by hardwareexecuting corresponding software. The hardware or the software includesone or more modules corresponding to the foregoing function.

According to a fifth aspect, an embodiment of this application providesa computer storage medium, configured to store a computer softwareinstruction used by the foregoing network device, and including aprogram designed for executing the first aspect or any possibleimplementation of the first aspect.

According to a sixth aspect, an embodiment of this application providesa computer storage medium, configured to store a computer softwareinstruction used by the foregoing terminal device, and including aprogram designed for executing the second aspect or any possibleimplementation of the second aspect.

According to a seventh aspect, an embodiment of this application furtherprovides a communications system, where the communications systemincludes the network device according to the third aspect or anypossible implementation of the third aspect and the terminal deviceaccording to the fourth aspect or any possible implementation of thefourth aspect.

BRIEF DESCRIPTION OF THE DRAWINGS

To describe the technical solutions in the embodiments of thisapplication more clearly, the following briefly describes theaccompanying drawings required for describing the embodiments.Apparently, the accompanying drawings in the following description showsome embodiments of this application, and a person of ordinary skill inthe art may still derive other drawings from these accompanying drawingswithout creative efforts.

FIG. 1 is a schematic diagram of a network system to which an embodimentof this application is applied;

FIG. 2 is a schematic structural diagram of a possible SSB listed in anembodiment of this application;

FIG. 3 is a schematic diagram of a sending period of a possible SSBburst set listed in an embodiment of this application;

FIG. 4 is a flowchart of a broadcast signal transmission methodaccording to an embodiment of this application;

FIG. 5 is a schematic diagram of a broadcast signal sending method withreference to a possible protocol stack structure according to anembodiment of this application;

FIG. 6A and FIG. 6B are a flowchart of a broadcast signal sending methodaccording to an embodiment of this application;

FIG. 7 is a schematic diagram of a broadcast signal sending methodaccording to an embodiment of this application;

FIG. 8A and FIG. 8B are a flowchart of another broadcast signal sendingmethod according to an embodiment of this application;

FIG. 9 is a schematic diagram of another broadcast signal sending methodaccording to an embodiment of this application;

FIG. 10 is a schematic diagram of another broadcast signal sendingmethod according to an embodiment of this application;

FIG. 11 is a schematic diagram of another broadcast signal sendingmethod according to an embodiment of this application;

FIG. 12 is a schematic diagram of another broadcast signal sendingmethod according to an embodiment of this application;

FIG. 13 is a flowchart of a broadcast signal sending method according toan embodiment of this application;

FIG. 14 is a schematic diagram of a broadcast signal sending methodaccording to an embodiment of this application;

FIG. 15 is a flowchart of a broadcast signal receiving method accordingto an embodiment of this application;

FIG. 16A and FIG. 16B are a flowchart of another broadcast signalreceiving method according to an embodiment of this application;

FIG. 17 is a schematic structural diagram of a network device accordingto an embodiment of this application;

FIG. 18 is a schematic structural diagram of another network deviceaccording to an embodiment of this application;

FIG. 19 is a schematic structural diagram of a terminal device accordingto an embodiment of this application; and

FIG. 20 is a schematic structural diagram of another terminal deviceaccording to an embodiment of this application.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

The following describes technical solutions of this application withreference to accompanying drawings.

FIG. 1 is a schematic diagram of a network system to which an embodimentof this application is applied. As shown in FIG. 1, a network system 100may include a network device 102 and terminal devices 104, 106, 108,110, 112, and 114. The network device and the terminal devices areconnected in a wireless manner. It should be understood that in FIG. 1,descriptions are based on only an example in which the network systemincludes one network device. However, the embodiments of the presentinvention are not limited herein. For example, the system mayalternatively include more network devices. Similarly, the system mayalternatively include more terminal devices.

This specification describes the embodiments with reference to aterminal device. The terminal device may alternatively be UE, an accessterminal, a mobile station, a remote station, a remote terminal, amobile device, a user terminal, or a user agent. Alternatively, theterminal device may be a handheld device having a wireless communicationfunction, a computing device, another processing device connected to awireless modem, an in-vehicle device, a wearable device, a terminaldevice in a future 5G network, a terminal device in a future evolvedpublic land mobile network (PLMN), or the like.

As an example rather than a limitation, in the embodiments of thepresent invention, the terminal device may also be a wearable device.The wearable device may also be referred to as a wearable intelligentdevice, and is a generic term for wearable devices such as glasses,gloves, watches, clothes, and shoes that are developed by applyingwearable technologies to intelligent designs of daily wear. The wearabledevice is a portable device that is directly worn on a body orintegrated into clothes or an accessory of a user. The wearable deviceis not only a hardware device, but implements a powerful functionthrough software support, data exchange, and cloud interaction.Generalized wearable intelligent devices include full-featured andlarge-size devices that can implement complete or partial functionswithout depending on smartphones, such as smart watches or smartglasses, and devices that focus only on one type of applicationfunctions and need to work with other devices such as smartphones, suchas various smart bands or smart jewelry for monitoring physical signs.In the embodiments of this application, UE is used as an example todescribe a structure and a processing procedure of the terminal device.

This specification describes the embodiments with reference to a networkdevice. The network device may be a device configured to communicatewith the terminal device. The network device may be a base transceiverstation (BTS) in global system for mobile communications (GSM) or codedivision multiple access (CDMA), or may be a NodeB (NB) in a widebandcode division multiple access (WCDMA) system, or may be an evolved NodeB(Evolutional Node B, eNB or eNodeB) in a long term evolution (LTE)system, or may be a radio controller in a cloud radio access network(CRAN) scenario, or a gNodeB (gNB) in a 5G network. In the embodimentsof this application, a base station is used as an example to describe astructure and a processing procedure of the network device.

FIG. 2 is a schematic structural diagram of a possible SSB. One SSBincludes a PSS (or a new radio PSS (NR-PSS)) of one OFDM symbol, an SSS(or a new radio SSS (NR-SSS)) of one OFDM symbol, and a PBCH (or a newradio PBCH (NR-PBCH)) of two OFDM symbols. The NR-PSS and the NR-SSS mayrespectively have functions of a PSS and an SSS in a conventionalstandard (for example, LTE). For example, the NR-PSS may be used todetermine OFDM symbol timing, frequency synchronization, slot timing,and a cell ID within a cell group. The NR-SSS may be used to determineframe timing, a cell group, or the like. Alternatively, the NR-PSS andthe NR-SSS may have functions different from those of a current PSS anda current SSS. This is not limited in this embodiment of the presentinvention. In addition, the NR-PSS and the NR-SSS may use sequences thatare separately the same as or different from those of a current PSS anda current SSS. This is not limited either in this embodiment of thepresent invention. In addition, in this embodiment of the presentinvention, the NR-PBCH may have a function the same as or different fromthat of a PBCH in a conventional standard (for example, LTE). This isnot limited either in the present invention. Optionally, the NR-PBCH maycarry a master information block (MIB).

It should be understood that a resource structure of the SSB shown inFIG. 2 is only a possible structure, and should not constitute anylimitation on this embodiment of the present invention. For example,quantities of subcarriers occupied by the NR-PSS, the NR-SSS, and theNR-PBCH in frequency domain may be different, and are not shown in thefigure. Alternatively, the NR-PSS, the NR-SSS, and the NR-PBCH may bediscontinuous in time. Alternatively, the SSB may only include theNR-PSS and the NR-PBCH, or only include the NR-SSS and the NR-PBCH, oreven may only include the NR-PBCH. The resource structure of the SSB isnot particularly limited in this embodiment of the present invention.

For how to carry additional information in the SSB, some researchproposes to carry additional information in an NR-PBCH resource includedin an SSB. The additional information is, for example, a sequence number(Time Index, TI) used to indicate an order of the SSB in a sendingperiod of an SS burst set to which the SSB belongs. However, how thebase station indicates the additional information in the NR-PBCHresource and how the UE reads the additional information of the SSB fromthe NR-PBCH resource are still problems to be resolved.

The additional information introduced due to the SSB may sometimes alsoimplement a plurality of function. Using a TI of the SSB as an example,not only the TI may indicate the order of the SSB in the sending periodof the SS burst set to which the SSB belongs, but also SSBs with a sameTI are all mapped to a relatively fixed time-frequency resource in thesending period of the SSB burst set to which the SSBs belong. Therefore,after obtaining a TI in one SSB, the UE may infer a boundary of aframe/slot of the cell based on content of the TI and a pre-learnedtime-frequency resource to which an SSB corresponding to each TI ismapped in the sending period of the SSB burst set, to implement timesequence alignment between the UE and a radio frame of the cell. FIG. 3is a schematic diagram of a possible SSB sending solution. In FIG. 3,each SS burst set sending period (periodicity) includes two radioframes, each radio frame is 10 ms, and a first radio frame of the SSburst set sending period includes eight SSBs. In each SS burst setsending period, an SSB 2 is mapped to a fixed time-frequency resource inthe SS burst set sending period. If the UE knows a TI of an SSB, forexample, TI=2, a boundary of a radio frame may be calculated.

However, it is relatively difficult for the UE to implement timesequence alignment based on the TI if a conventional solution forprocessing content transmitted on the PBCH is used. Referring to arelationship between protocol layers in a protocol stack of 5G and anexisting LTE network, if UE wants to obtain information transmitted on aPBCH, the UE needs to process, at a plurality of protocol layers, datareceived at a physical (PHY) layer, and report the data to radioresource control (RRC), so that the data is read by the RRC layer.Because signal processing at a plurality of protocol layers consumes arelatively long time, it is difficult to implement fast time sequencealignment between the UE and the cell, and a subsequent service delay iscaused.

The embodiments of the present invention provide a broadcast signaltransmission solution suitable for new radio (NR). Processing proceduresat lower protocol layers of the base station and the UE are improved,for example, a processing procedure at a physical layer is improved.From a perspective of the base station, a part of information to betransmitted on the PBCH is generated at a lower protocol layer (forexample, a physical layer) of the base station, and not all informationto be transmitted on the PBCH is generated at a higher protocol layer(for example, an RRC layer) and sent to the lower protocol layer. From aperspective of the UE, a lower protocol layer of the UE reads a part ofinformation transmitted on the PBCH, and control the UE at the lowerprotocol layer based on the read part of information, instead ofprocessing, at the lower protocol layer, data received on the PBCH,sending all information obtained by processing to a higher protocollayer for further processing, and then controlling the UE based oninformation obtained after processing at the higher protocol layer. Inthis way, a time consumed when the base station and the UE performprotocol layer processing on the part of information can be shortened,so that the UE can be quickly controlled based on the part ofinformation obtained by processing at the lower protocol layer, and asubsequent service delay is shortened. For example, the UE may quicklyimplement time sequence alignment with a cell based on a TI read at thephysical layer.

The following describes the technical solutions in this application indetail with reference to a plurality of accompanying drawings.

FIG. 4 is a flowchart of a broadcast signal transmission methodaccording to an embodiment of this application. In FIG. 4, a basestation is used as an example to describe the network device 102 inFIG. 1. UE in FIG. 4 may be the terminal devices 104, 106, 108, 110,112, and 114 in FIG. 1. FIG. 4 is mainly described from a perspective ofa base station.

Step 40: The base station generates first information at a firstprotocol layer. A protocol stack of the base station includes a firstprotocol layer and a second protocol layer, and the second protocollayer is a protocol layer below the first protocol layer.

In this application, the first protocol layer and the second protocollayer do not indicate a sequence relationship, and instead are used todistinguish between different protocol layers, and first information,second information, and the like mentioned below are also used todistinguish between different information.

Optionally, FIG. 5 is a schematic diagram of a broadcast signal sendingmethod with reference to a possible protocol stack structure accordingto an embodiment of this application. The protocol stack includes fiveprotocol layers that are respectively an RRC layer, a packet dataconvergence protocol (PDCP) layer, a radio link control (RLC) layer, amedia access control (MAC) layer, and a physical (PHY) layer from top tobottom.

It should be noted that, protocol layer division in a 5G network isstill under discussion, and the protocol stack shown in FIG. 5 may beimproved. For example, a plurality of protocol layers are combined, or anew protocol layer is added. In this embodiment, that the first protocollayer is the RRC layer is only used as an example for description,provided that it is ensured that a relative relationship between thefirst protocol layer and the second protocol layer is that the firstprotocol layer is a protocol layer above the second protocol layer.

Optionally, the first information includes system information. Thesystem information may be system information in an LTE network, or maybe system information defined in an NR standard. For example, the systeminformation includes a system bandwidth, a system frame number (SFN), orconfiguration information of remaining minimum system information(RMSI). The configuration information of the RMSI is used to indicate atime-frequency resource and a subcarrier spacing that are used totransmit the RMSI. Some bits in the SFN may be included in the systeminformation, and the other bits may be implicitly indicated bysubsequent scrambling at a physical layer. For example, the SFN has atotal of 10 bits, and the system information includes the first eightbits of the SFN. The last two bits of the SFN are implicitly indicatedby subsequent scrambling at the physical layer.

Step 41: The base station generates second information at the secondprotocol layer. Optionally, the second protocol layer is a MAC layer ora physical layer. The second information is additional information to becarried in a PBCH symbol of an SSB. The additional information isinformation related to the SSB. A network may implement more functionsbased on the additional information. For example, the second informationis used to determine a time-frequency resource corresponding to one ormore synchronization signal blocks SSBs.

Optionally, the second information is a TI of the SSB. When the basestation sends the first information and the second information, thephysical layer maps, to the time-frequency resource of the SSB indicatedby the TI, data obtained after physical layer processing is performed onthe first information and the second information. Specifically, thephysical layer subsequently carries, by using an OFDM symbol of the PBCHof the SSB indicated by the TI, the data obtained after physical layerprocessing is performed on the first information and the secondinformation.

Step 42: The base station processes the first information and the secondinformation at the second protocol layer.

If the second protocol layer is the MAC layer, second protocol layerprocessing includes determining, at the MAC layer, a format of data senton an air interface, for example, a size of a data block, and allocatinga physical layer resource based on the size of the data block, forexample, determining a modulation and coding scheme of the data block,and determining a quantity of subcarriers used to carry the data block.

For example, the second protocol layer is the MAC layer, the firstinformation is system information, and the second information is a TI.After the MAC receives the system information sent by the RRC layer byusing a broadcast control channel (BCCH) and a TI of an SSB generated bythe MAC layer, the MAC layer determines corresponding controlinformation. The control information includes a size of a data blockused to transmit the system information and the TI, a manner ofadjusting the data block, and a subcarrier used to carry the data block.Then, the MAC layer separately notifies a physical layer of the datablock used to transmit the system information and the TI, the controlinformation, and the like by using a broadcast channel (BCH), ornotifies the physical layer of a combination of the information by usingthe BCH, so that after performing physical layer processing on datareceived on the BCH, the physical layer sends data obtained afterphysical layer processing to the UE by using a physical broadcastchannel (PBCH).

If the second protocol layer is the physical layer, second protocollayer processing includes channel coding, rate matching, interleaving,scrambling, modulation, time-frequency resource mapping, inverse fastFourier transform (IFFT), and the like.

For example, the second protocol layer is the physical layer, the firstinformation is system information, and the second information is a TI.After receiving the system information and a TI of an SSB generated bythe physical layer, the physical layer performs the foregoing physicallayer processing on the system information and the TI. The systeminformation is generated by the RRC layer, is processed by the PDCPlayer, the RLC layer, and the MAC layer, and is notified to the physicallayer by using a BCH.

Step 43: The base station sends, to UE by using a PBCH in the SSB, dataobtained after second protocol layer processing, where the SSB is an SSBdetermined by the base station based on the second information.

If the second protocol layer is the MAC layer, step 43 specificallyincludes the following.

Step 1: The base station performs physical layer processing on dataobtained by processing at the MAC layer. The physical layer processingincludes channel coding, rate matching, interleaving, scrambling,modulation, and the like.

Step 2: The base station sends, to the UE by using the PBCH in the SSB,data obtained after physical layer processing.

If the second protocol layer is the physical layer, step 43 means thatthe base station sends, to the UE by using the PBCH in the SSB, the dataobtained after physical layer processing. Specifically, the base stationmaps, at the physical layer, the data obtained after physical layerprocessing to time-frequency resources specified by the SFN and thesecond information, to send the data to the UE.

In this embodiment of this application, a protocol stack of the networkdevice includes the first protocol layer and the second protocol layer,and the second protocol layer is a protocol layer below the firstprotocol layer. For the base station, first information in informationfinally transmitted on the PBCH is generated at the first protocollayer, second information is generated at the second protocol layer, andthe second information is used to determine the time-frequency resourcecorresponding to one or more synchronization signal blocks SSBs. Thesecond information may be sent to the UE on the PBCH only by beingprocessed at a protocol layer below the second protocol layer. Comparedwith a solution in which all information transmitted on the PBCH isprocessed in an entire protocol stack below the first protocol layer,this solution shortens a time consumed to process, in the protocolstack, the information transmitted on the PBCH, and helps shorten aservice delay.

In FIG. 6A and FIG. 6B and FIG. 7, that the second protocol layer inFIG. 4 is a physical layer is used as an example to further describe abroadcast signal sending method provided in the embodiments of thisapplication.

FIG. 6A and FIG. 6B are a flowchart of a broadcast signal transmissionmethod according to an embodiment of this application. In FIG. 6A andFIG. 6B, a base station is used as an example to describe the networkdevice 102 in FIG. 1. Further, in FIG. 6A and FIG. 6B, the broadcastsignal transmission method provided in this embodiment of thisapplication is described by using an example in which the first protocollayer is an RRC layer and the second protocol layer is a physical layer.

Step 600: A base station generates first information at an RRC layer.The first information includes system information. For description ofthe system information, refer to the description in the embodimentdescribed in FIG. 4. Details are not described herein again. The RRClayer performs abstract syntax notation one (ASN.1) encapsulation on thegenerated first information, and sends the first information on whichthe ASN.1 encapsulation is performed to a MAC layer by using a BCCH. TheMAC layer performs MAC layer processing on the received firstinformation on which the ASN.1 encapsulation is performed, and thensends the first information to the physical layer by using a BCH.

Step 601: The physical layer of the base station receives, via a datablock transmitted by the BCH, the first information on which MAC layerprocessing is performed, where the first information is systeminformation generated by the RRC layer.

Step 602: The physical layer of the base station generates secondinformation. Optionally, the second information is a TI of an SSB.

Step 603: The base station performs physical layer processing on thefirst information on which MAC layer processing is performed and thesecond information generated by the physical layer.

Optionally, if physical layer processing includes channel coding,scrambling, and modulation, the base station may perform, by using steps6031 to 6035, physical layer processing on the first information onwhich the MAC layer processing is performed and the second informationgenerated by the physical layer.

Step 6031: The base station combines the second information and thefirst information on which the MAC layer processing is performed.Optionally, the physical layer of the base station directly cascades,with the second information and a cyclic redundancy check (CRC) code,the first information on which the ASN.1 encapsulation and MAC layerprocessing are performed. The cascading specifically means that bits ofthe first information on which the ASN.1 encapsulation and MAC layerprocessing are performed, bits of the second information, and bits ofthe CRC code are successively connected.

Step 6032: The base station uses a combination result of the secondinformation and the first information on which the MAC layer processingis performed as a whole to perform channel coding. That is, the basestation performs channel coding on a cascaded result in step 6031.

Optionally, after the channel coding, processing such as rate matchingis further included, so that a quantity of information bits in a codingresult is consistent with a quantity of allocated time-frequencyresource grids after scrambling and/or modulation.

Step 6033: The base station performs scrambling processing on a resultof the channel coding and/or the rate matching by separately using oneof J different scrambling codes, to obtain a corresponding scramblingresult, where each of N different scrambling codes of the J scramblingcodes corresponds to one type of values of the last M bits of a systemframe number, J, N, and M are all natural numbers, 1≤N≤J, and N=M².

In this embodiment of this application, the physical layer determines,according to the SFN, a radio frame used to send data obtained afterphysical layer processing. A part of the SFN is indicated in the systeminformation, and another part is implicitly indicated by scrambling. Forexample, the first information includes the first eight bits of the SFN,and the last two bits of the SFN are implicitly indicated by using ascrambling code. The last two bits of the SFN have four possible valuesin total, which are specifically 00, 01, 10, and 11. Therefore, thereare a total of four scrambling code sequences. The scrambling codesequence may be a Zadoff-Chu (ZC) sequence, and each scrambling codesequence corresponds to one type of values of the last two bits of theSFN.

A scrambling code sequence 1 corresponds to the values 00 of the lasttwo bits of the SFN.

A scrambling code sequence 2 corresponds to the values 01 of the lasttwo bits of the SFN.

A scrambling code sequence 3 corresponds to the values 10 of the lasttwo bits of the SFN.

A scrambling code sequence 4 corresponds to the values 11 of the lasttwo bits of the SFN.

The base station selects a scrambling sequence corresponding to the lasttwo bits of the system frame number, to scramble a result of the channelcoding and/or the rate matching.

Optionally, in addition to indicating the last two bits of the SFN, theJ different scrambling codes may be further used to implicitly indicatesome bits of the TI. For example, there are a total of eight differentscrambling codes, and each scrambling code corresponds to values of thelast two bits of the SFN and 1 bit of the TI.

In FIG. 7, a schematic diagram is used to describe a processing processof step 604 and step 605 in FIG. 6A and FIG. 6B. The base station firstscrambles the result of the channel coding/rate matching at the physicallayer by using one scrambling code in the four scrambling codesequences, to obtain a scrambling result at the physical layer.

Step 6034: The base station performs modulation processing on thescrambling result at the physical layer, to obtain modulated data.

Optionally, the modulation scheme may be preconfigured, for example,quadrature phase shift keying (QPSK) modulation.

Step 6035: The base station maps the modulated data to a PBCH in the SSBcorresponding to a sequence number of the SSB, and performs IFFTprocessing on data mapped to each PBCH symbol, to obtain the dataobtained after physical layer processing.

Optionally, the base station performs the following two steps on themodulated data at the physical layer.

Step 1: The base station determines an L-bit frame number of a radioframe used to send the modulated data, where values of the first L-Mbits of the L-bit frame number are indicated in system information, andthere is a mapping relationship between values of the last M bits and ascrambling code sequence used to generate the modulated data.

Step 2: The base station maps the modulated data to the PBCH in the SSBcorresponding to the sequence number of the SSB, where a mapping resultis the data obtained after physical layer processing.

Still for example, the system information includes the first eight bitsof the SFN, and the last two bits of the SFN are implicitly indicated byusing a scrambling code. Table 1 indicates a correspondence between ascrambling code sequence obtained by scrambling, values of the last twobits of the SFN, and a scrambling result.

TABLE 1 Values of the last Scrambling sequence two bits of an SFNScrambling result ZC sequence 1 00 Scrambling result 1 ZC sequence 2 01Scrambling result 2 ZC sequence 3 10 Scrambling result 3 ZC sequence 411 Scrambling result 4

Table 2 indicates a mapping relationship between the values of the lasttwo bits of the SFN and a frame number used to transmit the SSB, where avalue of k is a natural number, and k is determined based on values ofthe first eight bits of the SFN that are included in the firstinformation.

TABLE 2 Values of the last two bits of an SFN Frame number 00 8k 01 8k +2 10 8k + 4 11 8k + 6

Referring to FIG. 7, if the last two bits of the system frame number are00, the physical layer maps the data obtained after modulation to aradio frame 8k. If the last two bits of the system frame number are 01,the physical layer maps the data obtained after modulation to a radioframe 8k+2. If the last two bits of the system frame number are 10, thephysical layer maps the data obtained after modulation to a radio frame8k+₄. If the last two bits of the system frame number are 11, thephysical layer maps the data obtained after modulation to a radio frame8k+6.

Optionally, because the TI may be used to determine a time-frequencyresource to which an SSB to which the data obtained after physical layerprocessing belongs is mapped in an SSB burst set sending period, on onehand, a frame number of a radio frame to which the data obtained afterphysical layer processing is mapped may be determined by performing step1. On the other hand, a time-frequency resource to which the dataobtained after physical layer processing is mapped in an SSB burst setsending period may be further determined by using the TI. For example,the base station pre-stores information about a time-frequency resourceto which an SSB indicated by each TI is mapped in an SSB burst setsending period. Time domain information in the information about thetime-frequency resource may be a relative value of the SSB relative to astart location of the SSB burst set sending period. After generating aTI at the physical layer, the base station may search for atime-frequency resource to which an SSB corresponding to the generatedTI is mapped in an SSB burst set sending period.

In conclusion, the base station completes resource mapping for themodulated data at the physical layer, that is, determines a frame numberof a radio frame used to transmit the data obtained after physical layerprocessing, and information about a specific time-frequency resource ina radio frame.

Step 604: The base station sends, to UE by using the PBCH in the SSB,the data obtained after physical layer processing.

In the broadcast signal sending method provided in this embodiment ofthis application, the first information in the information finallytransmitted by the base station on the PBCH is generated by the firstprotocol layer, and the second information is generated by the secondprotocol layer. The second information may be sent to the UE on the PBCHonly by being processed at a protocol layer below the second protocollayer. When performing physical layer processing on the firstinformation and the second information, the base station first uses thefirst information and the second information as a whole to performchannel coding. Scrambling processing is performed on a result ofchannel coding by separately using N different scrambling codes, toobtain a scrambling result corresponding to each of the N differentscrambling codes, where each of the N different scrambling codescorresponds to one type of values of the last M bits of the system framenumber, N and M are both natural numbers, and N=M². In this way, a partof the SFN is indicated by the first information, and another part ofthe SFN is implicitly indicated by scrambling. The base stationseparately performs modulation processing on the scrambling resultcorresponding to each scrambling code, to obtain N groups of data. Thebase station determines, based on the SFN and the second information, atime-frequency resource used to send the data obtained after physicallayer processing, and then sends, by using the time-frequency resourcedetermined on the PBCH, the data obtained after physical layerprocessing. When an SSB is sent by using this solution, some additionalinformation related to the SSB can be carried in a PBCH symbolcorresponding to the SSB.

In FIG. 8A and FIG. 8B and FIG. 9, that the second protocol layer inFIG. 4 is a physical layer is used as an example to further describe abroadcast signal sending method provided in the embodiments of thisapplication.

FIG. 8A and FIG. 8B are a flowchart of a broadcast signal transmissionmethod according to an embodiment of this application. In FIG. 8A andFIG. 8B, a base station is used as an example to describe the networkdevice 102 in FIG. 1. Further, in FIG. 8A and FIG. 8B, the broadcastsignal transmission method provided in this embodiment of thisapplication is described by using an example in which the first protocollayer is an RRC layer and the second protocol layer is a physical layer.

Step 800: A base station generates first information at an RRC layer.The first information includes system information. For description ofthe system information, refer to the description in the embodimentdescribed in FIG. 4. Details are not described herein again. The RRClayer performs ASN.1 encapsulation on the generated first information,and sends the first information on which the ASN.1 encapsulation isperformed to a MAC layer by using a BCCH. The MAC layer performs MAClayer processing on the received first information on which the ASN.1encapsulation is performed, and then sends the first information to thephysical layer by using a BCH.

Step 801: The physical layer of the base station receives, via a datablock transmitted by the BCH, the first information on which MAC layerprocessing is performed. The first information is system informationgenerated by the RRC layer.

Step 802: The physical layer of the base station generates secondinformation. For description of the second information, refer to thedescription in the foregoing embodiment. Optionally, in this embodiment,the second information is a TI of an SSB.

Step 803: The base station performs physical layer processing on thefirst information on which the MAC layer processing is performed and thesecond information generated by the physical layer.

Optionally, if the physical layer processing includes channel coding,scrambling, and modulation, the base station may perform, by using steps8031 to 8034, physical layer processing on the first information onwhich the MAC layer processing is performed and the second information.

Step 8031: The base station cascades, at the physical layer, the firstinformation on which the MAC layer processing is performed with a firstCRC code, and cascades the second information with a second CRC code.

Optionally, if the physical layer processing includes channel coding,scrambling, and modulation, the base station may perform, by using steps8031 to 8035, physical layer processing on a result of cascading thefirst information on which the MAC layer processing is performed and thefirst CRC code and a result of cascading the second information and thesecond CRC code.

For brevity, the result of cascading the first information on which theMAC layer processing is performed and the first CRC code is referred toas a first cascading result for short, and the result of cascading thesecond information and the second CRC code is referred to as a secondcascading result for short.

Step 8032: The base station performs channel coding and/or rate matchingon the first cascading result by using a first coding rate to obtain afirst coding result, and performs channel coding and/or rate matching onthe second cascading result by using a second coding rate to obtain asecond coding result.

Optionally, after encoding is performed at a relatively low coding rate,a decoding result obtained when UE performs corresponding decoding hasrelatively high reliability. For example, the TI, has a relatively hightimeliness requirement on control over a behavior of the UE, andtherefore, the second information may be encoded at a relatively lowcoding rate. In this way, the UE may not need to combine TIs detected ina plurality of frames, and may perform time sequence alignment basedonly on a TI detected in one frame, thereby greatly accelerating timesequence alignment. Therefore, when the coding rate is set, the firstcoding rate may be set to be greater than the second coding rate.

Optionally, after channel coding, processing such as rate matching isfurther included, so that a data volume in a coding result is consistentwith a quantity of allocated resource grids.

Step 8033: The base station performs scrambling processing on acombination of the first coding result and the second coding result byseparately using one of J different scrambling codes, to obtain acorresponding scrambling result, where each of N different scramblingcodes of the J scrambling codes corresponds to one type of values of thelast M bits of a system frame number, J, N, and M are all naturalnumbers, 1≤N≤J, and N=M².

For example, the first information includes the first eight bits of theSFN, and the last two bits of the SFN are implicitly indicated by usinga scrambling code. The last two bits of the SFN have four possiblevalues in total, which are specifically 00, 01, 10, and 11. Therefore,there are a total of four scrambling code sequences. The scrambling codesequence may be a Zadoff-Chu (ZC) sequence, and each scrambling codesequence corresponds to one type of values of the last two bits of theSFN.

A scrambling code sequence 1 corresponds to the values 00 of the lasttwo bits of the SFN.

A scrambling code sequence 2 corresponds to the values 01 of the lasttwo bits of the SFN.

A scrambling code sequence 3 corresponds to the values 10 of the lasttwo bits of the SFN.

A scrambling code sequence 4 corresponds to the values 11 of the lasttwo bits of the SFN.

In FIG. 9, a schematic diagram is used to describe a processing processof step 804 and step 805 in FIG. 8A and FIG. 8B. Optionally, acombination of the first coding result and the second coding result maybe scrambled by using one of different scrambling code sequences. Itshould be noted that a combination manner of the first coding result andthe second coding result may be the same or different each timescrambling is performed.

For example, in a first SS burst set period, each bit in the firstcoding result and each bit in the second coding result are placed atintervals to generate first combined data, and the first combined datais scrambled by using a ZC sequence 1 in a scrambling code group, toobtain a scrambling result.

For example, in a second SS burst set period, every two bits in thefirst coding result and every two bits in the second coding result areplaced at intervals to generate second combined data, and the secondcombined data is scrambled by using a ZC sequence 2 in the scramblingcode group, to obtain a scrambling result.

For example, in a third SS burst set period, the first coding result andthe second coding result are cascaded in such a way that the firstcoding result is before the second coding result, to generate thirdcombined data, and the third combined data is scrambled by using a ZCsequence 3 in the scrambling code group, to obtain a scrambling result.

For example, in a fourth SS burst set period, the first coding resultand the second coding result are cascaded in such a way that the secondcoding result is before the first coding result, to generate fourthcombined data, and the fourth combined data is scrambled by using a ZCsequence 4 in the scrambling code group, to obtain a scrambling result.

Step 8034: The base station performs modulation processing on thescrambling result at the physical layer, to obtain modulated data.

Optionally, the modulation scheme may be preconfigured, for example,QPSK modulation.

Step 8035: The base station maps the modulated data to a PBCH in the SSBcorresponding to a sequence number of the SSB, and performs IFFTprocessing on data mapped to each PBCH symbol, to obtain data after thephysical layer processing.

Optionally, the base station performs the following two steps on themodulated data at the physical layer.

Step 1: The base station determines an L-bit frame number of a radioframe used to send the modulated data, where values of the first L-Mbits of the L-bit frame number are indicated in system information, andthere is a mapping relationship between values of the last M bits and ascrambling code sequence used to generate the modulated data.

Step 2: The base station maps the modulated data to the PBCH in the SSBcorresponding to the sequence number of the SSB, where a mapping resultis the data obtained after physical layer processing.

Still for example, the first information includes the first eight bitsof the SFN, and the last two bits of the SFN are implicitly indicated byusing a scrambling code. Table 3 indicates a correspondence between ascrambling code sequence obtained by scrambling, values of the last twobits of the SFN, and a scrambling result.

TABLE 3 Values of the last Scrambling sequence two bits of an SFNScrambling result ZC sequence 1 00 Scrambling result 1 ZC sequence 2 01Scrambling result 2 ZC sequence 3 10 Scrambling result 3 ZC sequence 411 Scrambling result 4

Table 4 indicates a mapping relationship between the values of the lasttwo bits of the SFN and a frame number used to transmit the SSB, where avalue of k is a natural number, and k is determined based on the firsteight bits of the SFN that are included in the first information.

TABLE 4 Values of the last two bits of an SFN Frame number 00 8k 01 8k +2 10 8k + 4 11 8k + 6

Referring to FIG. 9, if the last two bits of the system frame number are00, the physical layer maps the data obtained after modulation to aradio frame 8k. If the last two bits of the system frame number are 01,the physical layer maps the data obtained after modulation to a radioframe 8k+2. If the last two bits of the system frame number are 10, thephysical layer maps the data obtained after modulation to a radio frame8k+4. If the last two bits of the system frame number are 10, thephysical layer maps the data obtained after modulation to a radio frame8k+6.

Optionally, because the TI may be used to determine a time-frequencyresource to which an SSB to which the data obtained after physical layerprocessing belongs is mapped in an SSB burst set sending period, on onehand, a frame number of a radio frame to which the data obtained afterphysical layer processing is mapped may be determined by performing step1. On the other hand, a time-frequency resource to which the dataobtained after physical layer processing is mapped in an SSB burst setsending period may be further determined by using the TI. For example,the base station pre-stores information about a time-frequency resourceto which an SSB indicated by each TI is mapped in an SSB burst setsending period. Time domain information in the information about thetime-frequency resource may be a relative value of the SSB relative to astart location of the SSB burst set sending period. After generating aTI at the physical layer, the base station may search for atime-frequency resource to which an SSB corresponding to the generatedTI is mapped in an SSB burst set sending period.

In conclusion, the base station completes resource mapping for themodulated data at the physical layer, that is, determines a frame numberof a radio frame used to transmit the data obtained after physical layerprocessing, and information about a specific time-frequency resource ina radio frame.

Step 804: The base station sends, to the UE by using the PBCH in theSSB, the data obtained after physical layer processing.

In the broadcast signal sending method provided in this embodiment ofthis application, the first information in the information transmittedby the base station on the PBCH is generated by the first protocollayer, and the second information is generated by the second protocollayer. The second information may be sent to the UE on the PBCH only bybeing processed at a protocol layer below the second protocol layer. Adifference from the embodiment shown in FIG. 6A and FIG. 6B is that whenperforming physical layer processing on the first information and thesecond information, the base station separately performs channel codingon the first information and the second information to obtain twochannel coding results. Scrambling processing is performed on acombination of the two channel coding results by separately using Ndifferent scrambling codes, to obtain a scrambling result correspondingto each of the N different scrambling codes. On the basis that an effectof the embodiment shown in FIG. 6A and FIG. 6B can be achieved, when thefirst information and the second information are encoded by usingdifferent coding rates, a lower coding rate is set for the secondinformation, to improve accuracy of detecting the second information bythe UE. Therefore, timeliness of controlling a behavior of the UE by aUE side based on the second information is improved, and a service delayis further shortened.

FIG. 10 is a schematic diagram of another physical layer processingprocess according to an embodiment of this application. During physicallayer processing, after separately scrambling a channel coding result offirst information and a channel coding result of second information, thebase station performs modulation and resource mapping on a combinationof the scrambling results. As shown in FIG. 10, at a physical layer, thebase station performs channel coding and/or rate matching on the firstinformation by using a first coding rate to obtain a first codingresult, and performs channel coding and/or rate matching on the secondinformation by using a second coding rate, to obtain a second codingresult. The base station separately performs scrambling processing onthe first coding result and the second coding result by using one of Jdifferent scrambling codes, to obtain a corresponding first scramblingresult and a corresponding second scrambling result, where each of Ndifferent scrambling codes of the J scrambling codes corresponds to onetype of values of the last M bits of a system frame number, N and M areboth natural numbers, i≤M≤J, and N=M². In FIG. 10, due to limited space,scrambling processing of data in one radio frame is only used as anexample for description, and cases of other three radio frames aresimilar. Further, the base station performs modulation processing on acombination of the first scrambling result and the second scramblingresult, to obtain modulated data. The base station maps the modulateddata to a PBCH in an SSB corresponding to a sequence number of the SSB,and performs IFFT processing on data mapped to each PBCH symbol, toobtain data processed by the physical layer.

FIG. 11 is a schematic diagram of another physical layer processingprocess according to an embodiment of this application. During physicallayer processing, after separately scrambling and modulating a channelcoding result of first information and a channel coding result of secondinformation, the base station performs resource mapping after results ofseparate modulation are combined. As shown in FIG. 11, at a physicallayer, the base station performs channel coding and/or rate matching onthe first information by using a first coding rate to obtain a firstcoding result, and performs channel coding and/or rate matching on thesecond information by using a second coding rate, to obtain a secondcoding result. The base station separately performs scramblingprocessing on the first coding result and the second coding result byseparately using one of J different scrambling codes, to obtain acorresponding first scrambling result and a corresponding secondscrambling result, where each of N different scrambling codes of the Jscrambling codes corresponds to one type of values of the last M bits ofa system frame number, J, N, and M are all natural numbers, 1≤N≤J, andN=M². Further, the base station separately performs modulationprocessing on the first scrambling result and the second scramblingresult, to obtain corresponding first modulated data and correspondingsecond modulated data. The base station maps a combination of the firstmodulated data and the second modulated data to a PBCH in an SSBcorresponding to a sequence number of the SSB, and performs IFFTprocessing on data mapped to each PBCH symbol, to obtain data after thephysical layer processing.

FIG. 12 is a schematic diagram of another physical layer processingprocess according to an embodiment of this application. During physicallayer processing, after separately scrambling and modulating a channelcoding result of first information and a channel coding result of secondinformation, the base station separately performs resource mapping, andthen performs IFFT on a mapped result. As shown in FIG. 12, the basestation performs channel coding and/or rate matching on the firstinformation by using a first coding rate to obtain a first codingresult, and performs channel coding and/or rate matching on the secondinformation by using a second coding rate, to obtain a second codingresult. The base station separately performs scrambling processing onthe first coding result and the second coding result by separately usingone of J different scrambling codes, to obtain a corresponding firstscrambling result and a corresponding second scrambling result, whereeach of N different scrambling codes of the J scrambling codescorresponds to one type of values of the last M bits of a system framenumber, J, N, and M are all natural numbers, 1≤N≤J, and N=M². Further,the base station separately performs modulation processing on the firstscrambling result and the second scrambling result, to obtaincorresponding first modulated data and corresponding second modulateddata. The base station maps the first modulated data to a first resourceof a PBCH in an SSB corresponding to a sequence number of the SSB, toobtain a first mapped result, and maps the second modulated data to asecond resource of the PBCH in the SSB corresponding to the sequencenumber of the SSB, to obtain a second mapped result. Optionally, theresource corresponding to the PBCH in the SSB includes two symbols intime domain and a section of subcarriers in frequency domain. The firstresource may be a first symbol in time domain and the second resource isa second symbol in time domain, and subcarrier ranges corresponding tothe first resource and the second resource are the same. Certainly, thePBCH in the SSB may be alternatively divided into the first resource andthe second resource in another division manner, for example, division ofa frequency domain subcarrier range. The base station separatelyperforms IFFT processing on the first mapped result and the secondmapped result, to obtain a first IFFT result and a second IFFT result,where the first IFFT result and the second IFFT result are data obtainedafter physical layer processing.

Similar to the embodiment shown in FIG. 8A and FIG. 8B, in physicallayer processing processes shown in FIG. 10 to FIG. 12, the base stationmay set a lower coding rate for the second information, to improveaccuracy of detecting the second information by the UE. Therefore,timeliness of controlling a behavior of the UE by a UE side based on thesecond information is improved, and a service delay is furthershortened. That is, the second coding rate is less than the first codingrate.

In FIG. 13, that the second protocol layer in FIG. 4 is a MAC layer isused as an example to further describe a broadcast signal sending methodprovided in the embodiments of this application. FIG. 14 is a schematicdiagram of a broadcast signal sending method with reference to apossible protocol stack structure according to an embodiment of thisapplication.

The broadcast signal sending method shown in FIG. 13 includes thefollowing steps.

Step 1300: A base station generates first information at an RRC layer.The first information includes system information. For description ofthe system information, refer to the description in the embodimentdescribed in FIG. 4. Details are not described herein again. The basestation performs ASN.1 encapsulation on the generated first informationat the RRC layer, and sends the first information on which the ASN.1encapsulation is performed to a MAC layer by using a BCCH.

Step 1301: The base station receives, at the MAC layer by using theBCCH, the first information on which the ASN.1 encapsulation isperformed.

Step 1302: The base station generates second information at the MAClayer. For description of the second information, refer to thedescription in the foregoing embodiment. Details are not describedherein again. Optionally, the second information is a TI of an SSB.

Step 1303: The base station sends, to a physical layer by using a BCH,the second information and the first information on which the ASN.1encapsulation is performed.

Step 1304: After obtaining, at the physical layer, the secondinformation and the first information on which the ASN.1 encapsulationis performed, where the second information and the first information aresent by the MAC layer by using the BCH, the base station performsphysical layer processing on the second information and the firstinformation on which the ASN.1 encapsulation is performed.

For a process in which the base station performs physical layerprocessing on the second information and the first information on whichthe ASN.1 encapsulation is performed, refer to the descriptions in FIG.6A and FIG. 6B to FIG. 9, and details are not described herein again.

Step 1305: The base station sends, to user equipment UE by using a PBCHin the SSB, data obtained after physical layer processing. For a processin which the base station sends, to the user equipment UE by using thePBCH, the data obtained after physical layer processing, refer to thedescriptions in FIG. 6A and FIG. 6B to FIG. 9, and details are notdescribed herein again.

FIG. 15 is a flowchart of a broadcast signal receiving method accordingto an embodiment of this application. In FIG. 15, UE is used as anexample to describe the terminal devices 104, 106, 108, 110, 112, and114 in FIG. 1. FIG. 15 is mainly described from a perspective of UE. TheUE in this embodiment may be the terminal device 102 in FIG. 1.Optionally, the UE may interact with the base station in FIG. 4 to FIG.14.

Step 151: The UE receives data sent by a base station by using a PBCH. Aprotocol stack of the UE includes a first protocol layer and a secondprotocol layer, and the first protocol layer is a protocol layer abovethe second protocol layer.

The protocol stack of the UE and a protocol stack of the base stationhave a similar structure, but functions of protocol layers aredifferent. For examples of protocol layers in the protocol stack of theUE, refer to FIG. 5 or FIG. 11. It should be noted that, protocol layerdivision in a 5G network is still under discussion, and the protocolstack shown in FIG. 5 may be improved, for example, a plurality ofprotocol layers are combined, or a new protocol layer is added.

Optionally, the first protocol layer is an RRC layer, and the secondprotocol layer is a MAC layer or a physical layer. In this embodiment,that the first protocol layer is an RRC layer is only used as an examplefor description, provided that it is ensured that a relativerelationship between the first protocol layer and the second protocollayer is that the first protocol layer is a protocol layer above thesecond protocol layer.

Step 152: The UE performs physical layer processing on the receiveddata.

Optionally, the physical layer processing includes fast Fouriertransform (FFT), demodulation, descrambling, de-interleaving, channeldecoding, and the like.

Step 153: The UE obtains, at the second protocol layer, firstinformation and second information from data obtained by physical layerprocessing.

Optionally, the first information includes system information. Fordescription of the system information, refer to the description in FIG.4. Repetitions are not described herein again.

Optionally, the second information is used to determine a time-frequencyresource corresponding to one or more synchronization signal blocks SSBscarrying the first information.

If the second protocol layer is the MAC layer, the MAC layer obtains, byusing a BCH, the data obtained by physical layer processing, processesthe data obtained from the BCH, and obtains the first information andthe second information from the data after MAC layer processing. The UEcontrols a behavior of the UE at the MAC layer based on the secondinformation, and sends the first information to an RRC layer by using aBCCH. The MAC layer processing includes decapsulation and the like.

If the second protocol layer is a physical layer, after performingphysical layer processing on the data received on the PBCH, the physicallayer obtains the first information and the second information from aphysical layer processing result.

Step 154: The UE controls a behavior of the UE at the second protocollayer based on the second information.

If the second protocol layer is the MAC layer, the UE controls thebehavior of the UE at the MAC layer based on the second information, andsends the first information to an RRC layer by using a BCCH.

If the second protocol layer is a physical layer, the UE controls thebehavior of the UE at the physical layer based on the secondinformation, and sends the first information to a MAC layer by using aBCH. Further, the UE sends the first information to an RRC layer at theMAC layer by using a BCCH.

For example, the second protocol layer is a physical layer, and thesecond information is a TI. After obtaining the TI, the physical layermay infer, based on a time-frequency resource used by the physical layerto receive the data and a pre-learned relative location of a resource towhich an SSB identified by the TI is mapped in an SSB burst set sendingperiod, a start location of the SSB burst set sending period to whichthe SSB carrying the data belongs, and uses the start location as aboundary of a radio frame of a cell, thereby implementing time sequencealignment.

The sending manner of the SSB shown in FIG. 3 is still used as anexample.

Assuming that the UE receives a PBCH symbol in an SSB 1 on atime-frequency resource 1, the UE may infer, based on a relativelocation to which the SSB 1 is mapped in an SSB burst set sendingperiod, a start location of the SSB burst set sending period to whichthe SSB 1 belongs, and uses the start location as a boundary of a radioframe of a cell, thereby implementing time sequence alignment.

Step 155: The UE controls the behavior of the UE at the first protocollayer based on the first information.

Optionally, for example, the first protocol layer is an RRC layer, andthe first information is system information. In this case, after readingthe system information at the RRC layer, the UE may learn a channelresource configuration status of the cell, to access the cell.

In the broadcast signal receiving method provided in this embodiment ofthis application, a protocol stack of the UE includes the first protocollayer and the second protocol layer, and the first protocol layer is aprotocol layer above the second protocol layer. The UE receives the datasent by the base station by using the PBCH. After the UE performsphysical layer processing on the received data, the UE obtains, at thesecond protocol layer, the first information and the second informationfrom data obtained by physical layer processing. The UE controls thebehavior of the UE at the second protocol layer based on the secondinformation, and controls the behavior of the UE at the first protocollayer based on the first information. After processing, at the physicallayer, the data sent on the PBCH, the UE does not need to report, to thefirst protocol layer for processing, all data obtained after physicallayer processing, and instead may directly read the second informationthereof, for example, information used to determine a time-frequencyresource corresponding to one or more synchronization signal blocksSSBs, at the second protocol layer, and control the behavior of the UEbased on the second information. Because a time taken by the UE toprocess the second information in a protocol stack is shortened, aservice delay can be shortened, and timeliness of a service can beimproved.

In FIG. 16A and FIG. 16B, that the second protocol layer in FIG. 15 is aphysical layer is used as an example to further describe a broadcastsignal receiving method provided in the embodiments of this application.

Step 161: UE detects a synchronization signal, and determines, by usingthe synchronization signal, a cell identifier and a time-frequencyresource that corresponds to a PBCH.

Step 162: The UE receives, on the time-frequency resource thatcorresponds to the PBCH, data sent by a base station by using the PBCH.

Step 163: The UE performs physical layer processing on the receiveddata.

Physical layer processing performed by the UE on received N groups ofdata corresponds to physical layer processing used when the base stationsends a broadcast signal. Optionally, if physical layer processing shownin FIG. 6A and FIG. 6B is used when the base station sends the broadcastsignal, physical layer processing performed by the UE on the received Ngroups of data includes steps 1630 to 1634. If physical layer processingshown in FIG. 8A and FIG. 8B is used when the base station sends thebroadcast signal, physical layer processing performed by the UE on thereceived N groups of data includes steps 1635 to 16310.

Step 1630: The UE performs FFT processing on the received data sent bythe base station by using the PBCH.

Step 1631: The UE demodulates data obtained by FFT processing, to obtaindemodulated data.

Step 1632: The UE obtains J descrambling sequences based on the cellidentifier obtained in step 161.

Step 1633: The UE selects a descrambling sequence from the Jdescrambling sequences to descramble the demodulated data.

Step 1634: The UE performs channel decoding on data obtained bydescrambling, performs CRC check on data obtained by the channeldecoding, to determine a descrambling sequence that can be used tocorrectly descramble the demodulated data, and uses a channel decodingresult obtained by correct descrambling as a physical layer processingresult, so that the UE obtains the first information and the secondinformation from the physical layer processing result.

Step 1635: The UE performs FFT processing on the received data sent bythe base station by using the PBCH.

Step 1636: The UE demodulates data obtained by FFT processing, to obtaindemodulated data.

Step 1637: The UE obtains J descrambling sequences based on the cellidentifier obtained in step 161.

Step 1638: The UE selects a descrambling sequence from the Jdescrambling sequences to descramble the demodulated data.

Step 1639: The UE obtains, from the descrambled data, first data andsecond data that are included thereof. A manner of obtaining the firstdata and the second data from a descrambling result corresponds to themanner of combining the first coding result and the second coding resultin step 8033 in FIG. 8A and FIG. 8B.

Step 16310: The UE performs channel decoding on the first data by usinga first decoding rate, performs CRC check on data obtained by thechannel decoding, to determine a descrambling sequence that can be usedto correctly descramble the demodulated data, and uses a channeldecoding result obtained by correct descrambling as the firstinformation.

The UE performs channel decoding on the second data by using a seconddecoding rate, and performs CRC check on the data obtained by thechannel decoding, to determine the descrambling sequence that can beused to correctly descramble the demodulated data. The channel decodingresult obtained by correct descrambling is used as the secondinformation. The UE uses the first information and the secondinformation as the physical layer processing result.

Optionally, to improve decoding accuracy, the UE may perform theforegoing processing on data received on PBCHs in a plurality of SSBs,to obtain a plurality of pieces of first data, combine the plurality ofpieces of first data, and then perform channel decoding on combinedfirst data by using the first decoding rate.

Optionally, corresponding to the coding rates, the first decoding rateis greater than the second decoding rate. Because a coding rate usedwhen the base station encodes the second information is relatively low,decoding accuracy of corresponding decoding performed by the UE isrelatively high. Therefore, when receiving any group of data sent by thebase station by using the PBCH, the UE may immediately performdemodulation and descrambling processing on the group of data, anddirectly decode the second data included in a descrambling result of thegroup of data, to obtain the second information.

Step 164: The UE obtains the first information and the secondinformation from the physical layer processing result.

Step 165: The UE controls a behavior of the UE at the physical layerbased on the second information.

Step 166: The UE sends the obtained first information to a MAC layer atthe physical layer by using a BCH, and the MAC layer further sends thefirst information to an RRC layer by using a BCCH.

Step 167: The UE controls the behavior of the UE at the RRC layer basedon the first information.

Corresponding to that the base station uses physical layer processingprocess shown in FIG. 10, FIG. 11, or FIG. 12, the UE may use acorresponding physical layer processing process for the data receivedfrom the PBCH in the SSB. A principle is similar to that in FIG. 16A andFIG. 16B, and details are not described herein again.

An embodiment of this application further provides a network device. Forexample, the network device is a base station. The following describes astructure and a function of the network device with reference to FIG. 17by using a base station as an example. FIG. 17 is a schematic structuraldiagram of a network device. The network device serves as the networkdevice in FIG. 1, and the base station in FIG. 4 to FIG. 14, toimplement functions of the network device in FIG. 1 and the base stationin the embodiments shown in FIG. 4 to FIG. 14. As shown in FIG. 17, thenetwork device includes a transceiver 171 and a processor 172.

Optionally, the transceiver 171 may be referred to as a remote radiounit (RRU), a transceiver unit, a transceiver, a transceiver circuit, orthe like. The transceiver 171 may include at least one antenna 1711 anda radio frequency unit 1712. The transceiver 171 may be configured toreceive and send a radio frequency signal, and perform conversionbetween a radio frequency signal and a baseband signal.

Optionally, the network device includes one or more baseband units (BBU)173. The baseband unit includes the processor 172. The baseband unit 173is mainly configured to perform baseband processing, such as channelcoding, multiplexing, modulation, spectrum spreading, and control thebase station. The transceiver 171 and the baseband unit 173 may bephysically disposed together or may be physically separated from eachother, that is, a distributed base station.

In an example, the baseband unit 173 may include one or more boards, anda plurality of boards may jointly support a radio access network of asingle access standard, or may separately support radio access networksof different access standards. The baseband unit 173 includes theprocessor 172. The processor 172 may be configured to control thenetwork device to perform corresponding operations in the foregoingmethod embodiments. Optionally, the baseband unit 173 may furtherinclude a memory 174, configured to store a necessary instruction andnecessary data.

The processor 172 is configured to generate first information at a firstprotocol layer, where a protocol stack of the network device includesthe first protocol layer and a second protocol layer, and the secondprotocol layer is a protocol layer below the first protocol layer, andgenerate second information at the second protocol layer, where thesecond information is used to determine a time-frequency resourcecorresponding to one or more synchronization signal blocks SSBs.

The processor 172 is further configured to process the first informationand the second information at the second protocol layer.

The transceiver 171 is configured to send, to UE by using a PBCH in theSSB, data obtained after second protocol layer processing.

Optionally, the first information includes system information. Thesystem information includes one or more of the following: a systembandwidth parameter value, an SFN, or configuration information of RMSI.

Optionally, the second protocol layer is a MAC layer or a physicallayer. The first protocol layer is an RRC layer.

If the second protocol layer is a MAC layer, the sending, to UE by usinga PBCH in the SSB, data obtained after second protocol layer processingincludes performing, by the processor 172, physical layer processing onthe data obtained by second protocol layer processing, and sending, bythe transceiver 171 to the UE by using a PBCH symbol in thetime-frequency resource corresponding to the SSB, data obtained afterphysical layer processing.

Optionally, for a specific manner in which the processor 172 performsMAC layer processing on the first information and the second informationat the MAC layer, refer to related descriptions in FIG. 13 and FIG. 14,and repetitions are not described herein again.

Optionally, for a specific manner in which the processor 172 performsphysical layer processing on the first information and the secondinformation at the physical layer, refer to descriptions in theforegoing method embodiments, especially to related descriptions in FIG.6A and FIG. 6B to FIG. 12, and repetitions are not described hereinagain.

An embodiment of this application further provides a network device. Forexample, the network device is a base station. The following describes astructure and a function of the network device with reference to FIG. 18by using a base station as an example. FIG. 18 is a schematic structuraldiagram of a network device. The network device serves as the networkdevice in FIG. 1, and the base station in FIG. 4 to FIG. 14, and hasfunctions of the network device in FIG. 1 and the base station in theembodiments shown in FIG. 4 to FIG. 14. As shown in FIG. 18, the networkdevice includes a transceiver unit 181 and a processing unit 182. Thetransceiver unit 181 and the processing unit 182 may be implemented bysoftware or hardware. When being implemented by hardware, thetransceiver unit 181 may be the transceiver 181 in FIG. 17, and theprocessing unit 182 may be the processor 172 in FIG. 17.

An embodiment of this application provides a network device, forexample, a base station. A protocol stack of the network device includesa first protocol layer and a second protocol layer, and the secondprotocol layer is a protocol layer below the first protocol layer. Forthe network device, first information in information finally transmittedon a PBCH is generated at the first protocol layer of the networkdevice, second information is generated at the second protocol layer ofthe network device, and the second information is used to determine atime-frequency resource corresponding to one or more synchronizationsignal blocks SSBs. The second information may be sent to UE on the PBCHonly by being processed at a protocol layer below the second protocollayer. Compared with a solution in which all information transmitted onthe PBCH is processed in an entire protocol stack below the firstprotocol layer, this solution shortens a time consumed to process, inthe protocol stack, the information transmitted on the PBCH, and helpsshorten a service delay.

An embodiment of this application further provides a terminal device. Itshould be understood that the terminal device may be the UE in theforegoing method embodiments, and may have any function of the UE in themethod embodiments. FIG. 19 is a schematic structural diagram of aterminal device. The terminal device serves as the UE in FIG. 1, and theUE in FIG. 15 and FIG. 16A and FIG. 16B, to implement functions of theUE in an embodiment shown in FIG. 1, FIG. 15, or FIG. 16A and FIG. 16B.As shown in FIG. 19, the terminal device includes a processor 191 and atransceiver 192.

Optionally, the transceiver 192 may include a control circuit and anantenna. The control circuit may be configured to perform conversionbetween a baseband signal and a radio frequency signal, and process aradio frequency signal, and the antenna may be configured to transmitand receive radio frequency signals.

Optionally, the apparatus may further include other main components ofthe terminal device, for example, a memory and input/output apparatus.

The processor 191 may be configured to process a communication protocoland communication data, control the entire terminal device, execute asoftware program, and process data of the software program, for example,configured to support the terminal device in performing a correspondingoperation in the foregoing method embodiments. A memory 193 is mainlyconfigured to store a software program and data. After the terminaldevice is powered on, the processor 191 may read a software program inthe memory, interpret and execute an instruction of the softwareprogram, and process data of the software program.

In an embodiment, the transceiver 192 is configured to receive data sentby a base station by using a PBCH. The terminal device includes a firstprotocol layer and a second protocol layer, and the first protocol layeris a protocol layer above the second protocol layer.

The processor 191 is configured to perform physical layer processing onthe received data, obtain, at the second protocol layer, firstinformation and second information from a physical layer processingresult, where the second information is used to determine atime-frequency resource corresponding to one or more synchronizationsignal blocks SSBs, control, at the second protocol layer, a behavior ofthe terminal device based on the second information, and control, at thefirst protocol layer, the behavior of the terminal device based on thefirst information.

Optionally, the first information is system information. Fordescriptions of the system information, refer to the descriptions in theforegoing embodiments. Repetitions are not described herein again.

Optionally, the first protocol layer is an RRC layer, and the secondprotocol layer is a physical layer or a MAC layer.

Optionally, for a process in which the transceiver 192 receives the datathat is sent by the base station by using the PBCH and a process inwhich the processor 191 performs physical layer processing on thereceived data, refer to the descriptions in the foregoing methodembodiments, especially to related descriptions in FIG. 1 and FIG. 15 toFIG. 16A and FIG. 16B. Details are not described herein again.

An embodiment of this application further provides a terminal device. Itshould be understood that the UE may be the UE in the foregoing methodembodiments, and may have any function of the UE in the methodembodiments. FIG. 20 is a schematic structural diagram of UE. The UEserves as the UE in FIG. 1, FIG. 15, and FIG. 16A and FIG. 16B, andimplements functions of the UE in an embodiment of FIG. 1, FIG. 15, andFIG. 16A and FIG. 16B. As shown in FIG. 20, the base station includes aprocessing unit 201 and a transceiver unit 202. The processing unit 201and the transceiver unit 202 may be implemented by software or hardware.When being implemented by hardware, the processing unit 201 may be theprocessor 191 in FIG. 19, and the transceiver unit 202 may be thetransceiver 192 in FIG. 19.

An embodiment of this application provides a terminal device. A protocolstack of the terminal device includes a first protocol layer and asecond protocol layer, and the first protocol layer is a protocol layerabove the second protocol layer. The terminal device receives data sentby a base station by using a PBCH. After UE performs physical layerprocessing on the received data, the terminal device obtains, at thesecond protocol layer, first information and second information fromdata obtained by physical layer processing. The UE controls a behaviorof the terminal device at the second protocol layer based on the secondinformation, and controls the behavior of the terminal device at thefirst protocol layer based on the first information. After processing,at the physical layer, the data sent on the PBCH, the terminal devicedoes not need to report, to the first protocol layer for processing, alldata obtained after physical layer processing, and instead may directlyread the second information thereof at the second protocol layer, andcontrol the behavior of the terminal device based on the secondinformation. Because a time taken by the terminal device to process thesecond information in a protocol stack is shortened, a service delay canbe shortened, and timeliness of a service can be improved.

An embodiment of the present invention further provides a communicationssystem, including the network device and the terminal device in theforegoing embodiments. For functions of the network device and theterminal device and a detailed process of mutual information exchange,refer to descriptions in the foregoing embodiments.

It may be clearly understood by a person skilled in the art that, forthe purpose of convenient and brief description, for a detailed workingprocess of the foregoing system, apparatus, and unit, refer to acorresponding process in the foregoing method embodiments, and detailsare not described herein again.

All or some of the foregoing embodiments may be implemented by usingsoftware, hardware, firmware, or any combination thereof. When softwareis used to implement the embodiments, the embodiments may be implementedcompletely or partially in a form of a computer program product. Thecomputer program product includes one or more computer instructions.When the computer program instructions are loaded and executed on acomputer, the procedure or functions according to the embodiments of thepresent invention are completely or partially generated. The computermay be a general-purpose computer, a dedicated computer, a computernetwork, or other programmable apparatuses. The computer instructionsmay be stored in a computer-readable storage medium or may betransmitted from a computer-readable storage medium to anothercomputer-readable storage medium. For example, the computer instructionsmay be transmitted from a website, computer, server, or data center toanother website, computer, server, or data center in a wired (forexample, a coaxial cable, an optical fiber, or a digital subscriber line(DSL)) or wireless (for example, infrared, radio, and microwave) manner.The computer-readable storage medium may be any usable medium accessibleby a computer, or a data storage device, such as a server or a datacenter, integrating one or more usable media. The usable medium may be amagnetic medium (for example, a floppy disk, a hard disk, or a magnetictape), an optical medium (for example, a DVD), a semiconductor medium(for example, a solid-state drive Solid State Disk (SSD)), or the like.

The foregoing descriptions are merely specific implementations of thepresent invention, but are not intended to limit the protection scope ofthe present invention. Any variation or replacement readily figured outby a person skilled in the art within the technical scope disclosed inthe present invention shall fall within the protection scope of thepresent invention. Therefore, the protection scope of the presentinvention shall be subject to the protection scope of the claims.

1-36. (canceled)
 37. A broadcast signal sending method, comprising:generating, by a network device, first information at a first protocollayer of a protocol stack of the network device that comprises the firstprotocol layer and a physical layer, wherein the first protocol layer isa protocol layer above the physical layer; generating, by the networkdevice, second information at the physical layer, wherein the secondinformation is used to determine a time-frequency resource correspondingto a synchronization signal block (SSB); processing, by the networkdevice, the first information and the second information at the physicallayer; and sending, by the network device to a terminal device by usinga physical broadcast channel (PBCH) in the SSB, data obtained afterphysical layer processing.
 38. The method according to claim 37, whereinthe second information comprises one or more bits of a sequence numberof the SSB.
 39. The method according to claim 38, wherein the secondinformation comprises a sequence number of the SSB.
 40. The methodaccording to claim 37, wherein a scrambling code used for scramblingprocessing in the physical layer processing corresponds to one or morebits of a sequence number of the SSB.
 41. A broadcast signal receivingmethod, comprising: receiving, by a terminal device, data sent by anetwork device by using a physical broadcast channel (PBCH), wherein aprotocol stack of the terminal device comprises a first protocol layerand a physical layer, and wherein the first protocol layer is a protocollayer above the physical layer; performing, by the terminal device,physical layer processing on the received data; and obtaining, by theterminal device at the physical layer, data related to first informationand second information from a physical layer processing result, whereinthe second information is used to determine a time-frequency resourcecorresponding to a synchronization signal block (SSB) carrying the firstinformation, and wherein the data related to the first information andsecond information is processed at a protocol layer above the physicallayer to obtain the first information.
 42. The method according to claim41, wherein the second information comprises one or more bits of asequence number of the SSB.
 43. The method according to claim 42,wherein the second information comprises a sequence number of the SSB.44. The method according to claim 41, wherein a scrambling code used fordescrambling in the physical layer processing corresponds to one or morebits of a sequence number of the SSB.
 45. A network device, comprising:a transceiver; a processor; and a non-transitory computer-readablestorage medium storing a program to be executed by the processor, theprogram including instructions to: generate first information at firstprotocol layer, wherein a protocol stack of the network device comprisesa first protocol layer and a physical layer, and wherein the firstprotocol layer is a protocol layer above the physical layer; generatesecond information at the physical layer, wherein the second informationis used to determine a time-frequency resource corresponding to asynchronization signal block (SSB); process the first information andthe second information at the physical layer; and cause the transceiverto send, to a terminal device by using a physical broadcast channel(PBCH) in the time-frequency resource corresponding to the SSB, dataobtained after physical layer processing.
 46. The network deviceaccording to claim 45, wherein the second information comprises one ormore bits of a sequence number of the SSB.
 47. The network deviceaccording to claim 46, wherein the second information comprises asequence number of the SSB.
 48. The network device according to claim45, wherein a scrambling code used for scrambling processing in thephysical layer processing corresponds to one or more bits of a sequencenumber of the SSB.
 49. A terminal device, comprising: a transceiver; aprocessor; and a non-transitory computer-readable storage medium storinga program to be executed by the processor, the program includinginstructions to: receive, through the transceiver, data sent by anetwork device by using a physical broadcast channel (PBCH), wherein aprotocol stack of the terminal device comprises a first protocol layerand a physical layer, and wherein the first protocol layer is a protocollayer above the physical layer; perform physical layer processing on thereceived data; and obtain, at the physical layer, data related to firstinformation and second information from a physical layer processingresult, wherein the second information is used to determine atime-frequency resource corresponding to a synchronization signal block(SSB) carrying the first information, and wherein the data related tothe first information and second information is processed at a protocollayer above the physical layer to obtain the first information.
 50. Theterminal device according to claim 49, the second information comprisesone or more bits of a sequence number of the SSB.
 51. The terminaldevice according to claim 50, wherein the second information comprises asequence number of the SSB.
 52. The terminal device according to claim49, wherein a scrambling code used for descrambling in the physicallayer processing corresponds to one or more bits of a sequence number ofthe SSB.
 53. A non-transitory computer storage medium, storing computerinstructions that, when executed by a network device, cause the networkdevice to perform: generating first information at a first protocollayer which is a protocol layer above a physical layer; generatingsecond information at the physical layer, wherein the second informationis used to determine a time-frequency resource corresponding to asynchronization signal block (SSB); processing the first information andthe second information at the physical layer; and sending, to a terminaldevice by using a physical broadcast channel (PBCH) in the SSB, dataobtained after physical layer processing.
 54. A non-transitory computerstorage medium, storing computer instructions that, when executed by anetwork device, cause the network device to perform: receiving aphysical broadcast channel (PBCH) carrying data from a network device;performing physical layer processing on the received data; and obtainingdata related to first information and second information from a physicallayer processing result, wherein the second information is used todetermine a time-frequency resource corresponding to a synchronizationsignal block (SSB) carrying the first information, and wherein the datarelated to the first information and second information is processed ata protocol layer above the physical layer to obtain the firstinformation.
 55. The non-transitory computer storage medium according toclaim 54, wherein the second information comprises one or more bits of asequence number of the SSB.
 56. The non-transitory computer storagemedium according to claim 54, wherein a scrambling code used fordescrambling in the physical layer processing corresponds to one or morebits of a sequence number of the SSB.